1package vars; 2 3use 5.006; 4 5our $VERSION = '1.03'; 6 7use warnings::register; 8use strict qw(vars subs); 9 10sub import { 11 my $callpack = caller; 12 my (undef, @imports) = @_; 13 my ($sym, $ch); 14 foreach (@imports) { 15 if (($ch, $sym) = /^([\$\@\%\*\&])(.+)/) { 16 if ($sym =~ /\W/) { 17 # time for a more-detailed check-up 18 if ($sym =~ /^\w+[[{].*[]}]$/) { 19 require Carp; 20 Carp::croak("Can't declare individual elements of hash or array"); 21 } elsif (warnings::enabled() and length($sym) == 1 and $sym !~ tr/a-zA-Z//) { 22 warnings::warn("No need to declare built-in vars"); 23 } elsif (($^H &= strict::bits('vars'))) { 24 require Carp; 25 Carp::croak("'$_' is not a valid variable name under strict vars"); 26 } 27 } 28 $sym = "${callpack}::$sym" unless $sym =~ /::/; 29 *$sym = 30 ( $ch eq "\$" ? \$$sym 31 : $ch eq "\@" ? \@$sym 32 : $ch eq "\%" ? \%$sym 33 : $ch eq "\*" ? \*$sym 34 : $ch eq "\&" ? \&$sym 35 : do { 36 require Carp; 37 Carp::croak("'$_' is not a valid variable name"); 38 }); 39 } else { 40 require Carp; 41 Carp::croak("'$_' is not a valid variable name"); 42 } 43 } 44}; 45 461; 47__END__ 48 49=head1 NAME 50 51vars - Perl pragma to predeclare global variable names 52 53=head1 SYNOPSIS 54 55 use vars qw($frob @mung %seen); 56 57=head1 DESCRIPTION 58 59NOTE: For use with variables in the current package for a single scope, the 60functionality provided by this pragma has been superseded by C<our> 61declarations, available in Perl v5.6.0 or later, and use of this pragma is 62discouraged. See L<perlfunc/our>. 63 64This will predeclare all the variables whose names are 65in the list, allowing you to use them under "use strict", and 66disabling any typo warnings. 67 68Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and 69C<use subs> declarations are not BLOCK-scoped. They are thus effective 70for the entire file in which they appear. You may not rescind such 71declarations with C<no vars> or C<no subs>. 72 73Packages such as the B<AutoLoader> and B<SelfLoader> that delay 74loading of subroutines within packages can create problems with 75package lexicals defined using C<my()>. While the B<vars> pragma 76cannot duplicate the effect of package lexicals (total transparency 77outside of the package), it can act as an acceptable substitute by 78pre-declaring global symbols, ensuring their availability to the 79later-loaded routines. 80 81See L<perlmodlib/Pragmatic Modules>. 82 83=cut 84